Bottles and debris were thrown at officers trying to break up a number of fights that broke out this week at Fremont High School in South Los Angeles, where pepper spray was used to restore order and eight students were detained.

One student sustained a minor injury and was taken to a hospital after the fights broke out around 11:30 a.m. Tuesday at the school in the 7600 block of San Pedro Street, according to Los Angeles School Police Department Sgt. Rudy Perez.

It was unclear what sparked the unrest. One student told KTLA 5 News that a small altercation between some girls quickly developed into several large fights.

According to Perez, while officers tried to break up a fight between two girls, bottles and debris were thrown at them and numerous other skirmishes broke out.

A bottle—unknown to Perez whether it was glass or plastic—reportedly struck an officer in the head, leading to an “officer-needs-help” call.

More than 30 officers, some of them from the Los Angeles Police Department, ultimately responded to the campus, Perez said.

Pepper spray was used in the course of holding one of the detained students, all of whom were turned over to their parents or guardians, Perez said.

The injured officer was treated at the scene, as were a number of other students, Perez said.

None of those detained were arrested and discipline would be addressed by school administration, according to Perez, who said there would be a highly visible police presence on the campus in the next few days.